Diamond grinding wheels are commonly used for shaping hard materials such as carbide tools. These wheels comprise particles of diamonds held together by a matrix material such as a resin binder. With many of the shapes desired for the carbide tools it is necessary that the grinding wheel have its periphery formed to a particular shape. The principal object of the present invention is to provide an apparatus by which a desired shape can be given to the periphery of a diamond wheel.
Numerous devices are available for shaping the periphery of grinding wheels formed of a refractory abrasive, such as Carborundum. In the main, the forming tool of such devices is a diamond. Since the diamond is harder than the refractory abrasive it acts to remove portions of the refractory abrasive from the periphery of the rotating wheel and the periphery of the wheel is thereby given the desired configuration. However, with a diamond wheel the diamonds on the wheel are just as hard as the diamond cutting tool and present much more surface area. Thus the cutting tool is abraded away before any significant amount of shaping is done to the grinding wheel. So far as I am aware, there is no apparatus presently available on the market for shaping a diamond grinding wheel and such shaping, when it is done, is performed as a hand operation. In such hand operation, diamond particles about the periphery of the wheel are broken away, nearly one at a time, until the whole of the periphery of the wheel has been so shaped. Not only is this a slow operation, and therefore expensive in terms of the workman's time involved, but it is tedious and it is nearly impossible to have all of the circumference of the wheel exactly the same configuration.
I have discovered that if the cutting tool is in the form of a tube and a part of the end of the tube is positioned in contact with the periphery of the wheel, approximately transverse to a tangent to the wheel, the contact between that part of the tube and the rotating wheel will break the diamonds away by destroying the bond of the matrix holding the diamonds together. This occurs even though the material of the tube is quite soft as compared to the hardness of the diamonds of the wheel. This is not to say that the tube is not abraded, but in my invention the tube is rotated about its longitudinal axis and the final position of the end of the tube is always fixed by contact with a stop which bears against another part of the end of the tube.
Further features and advantages of my invention may be determined from the subsequent description thereof herein.